1. Field of the Invention
The present invention relates to conveying devices of which the components are linked together such that the distance between them varies as well as their speed.
2. Description of the Prior Art
The stretchable bandconveyor is a bandconveyor made of a succession of components sliding into or above each other and linked to each other by devices varying the distance between them such that the visible length and the speed of the components vary along their course.
The stretchable train of cars is an endless succession of cars linked to each other by devices varying the distance between them.
The stretchable and endless train of cars is used in combination with bandconveyors at loading/unloading stations where the speed of the cars and the distance between them is at a minimum and is synchronized over some distance with the speed of the bandconveyors in order to enable people to go from the bandconveyors to the cars and vice versa.
Several variable speed bandconveyors are known in the prior art. One such device uses components which are longer than they are wide. These components slide along each other, while the relative direction of motion progressively changes from a direction perpendicular to the long side of the components to a direction parallel to it, and therefore, the speed of the components varies proportionally to the ratio of their length and width. Another example of a rotating-type conveying apparatus is illustrated in U.S. Pat. No. 3,485,182. In another existing device components are driven by a single threaded rod with variable pitch.
Bandconveyors are also known which operate at constant speeds and go into or out of cars moving at the same speed. Usually, those cars are attached to a cable moving at constant speed, and the distance between them is fixed. These prior art devices do not utilize controllable means for coupling the components and/or cars to achieve variable speed and variable distance operation while maintaining the components aligned, i.e. unrotated, with respect to the closed-loop path followed by the components.